To edit butterfly genomes, scientists used CRISPR, a naturally occurring series of DNA sequences in bacteria. CRISPR is a part of a gene-editing technique sometimes nicknamed “molecular scissors” for the way it can cut into strands of DNA.

Using CRISPR, scientists involved in the butterfly study deleted WntA (“wint-ay”), a signaling gene they knew was important in determining wing patterns.

Photograph by Willard Culver, National Geographic

Why are butterflies and butterfly wing patterns valuable in the study of genetics?

Butterflies are valuable to scientists for their sheer diversity. There are more than 20,000 species of butterfly alive today, all descended from a single species of moth, and examples of most butterfly species are preserved as specimens in museums.